In an automotive vehicle that is powered by an internal combustion engine, fuel may be pumped through a fuel handling system of the engine by an in-tank, electric-motor-operated fuel pump.
Examples of fuel pumps are shown in various patents, including U.S. Pat. Nos. 3,851,998; 5,310,308; 5,409,357; 5,415,521; 5,551,875; and 5,601,398. Commonly owned U.S. Pat. Nos. 5,310,308; 5,409,357; and 5,551,835 disclose pumps of the general type to which the present invention relates, and such pumps provide certain benefits and advantages over certain other types of pumps. One benefit of such pumps is that a number of its parts may be fabricated from polymeric (i.e. plastic) materials.
Through the continuing development of such pumps, it has been discovered that the presence of certain particulate material in commercial fuel may abraid such synthetic materials and thereby encourage wearing of pump parts made of such materials. Because vanes of a plastic impeller of such a pump are quite small, and because running clearances between pumping chamber walls and such an impeller may also be small, it is believed desirable to reduce the extent of interaction of such particulate material with the internal pumping mechanism. Because an automotive vehicle manufacturer cannot at the present time reasonably rely on commercial fuel refiners to improve fuel purity, it has become incumbent on the vehicle manufacturer to find a solution.